Infrared sensor manufacturing method suitable for mass production

Abstract

An infrared sensor manufacturing method according to this invention includes a step of forming a bridge structure of an insulating material on an Si substrate, a step of forming a vanadium oxide thin film on the bridge structure by a dry film forming method, a step of irradiating laser light onto the vanadium oxide thin film to thereby change material properties thereof, a step of forming the vanadium oxide thin film with the changed material properties into a bolometer resistor having a predetermined pattern, and a step of forming a protective layer of an insulating material so as to cover the bolometer resistor having the predetermined pattern and the bridge structure.

1. A method of manufacturing a bolometer-type infrared sensor that changes a temperature of a light-incident portion thereof by absorption of incident infrared light so as to change an electrical resistance value of a resistor by a temperature change, thereby outputting a signal indicative of a radiation intensity of the incident infrared light, said method comprising the steps of:
 forming a bridge structure of an insulating material on an insulating substrate; 
 forming a vanadium oxide thin film on said bridge structure by a dry film forming method; 
 irradiating laser light onto said vanadium oxide thin film to thereby change material properties thereof; 
 forming said vanadium oxide thin film with the changed material properties into a predetermined pattern as said resistor; and 
 forming a protective layer of an insulating material so as to cover said vanadium oxide thin film formed into the predetermined pattern and said bridge structure. 
 
     
     
       2. A method according to  claim 1 , wherein said dry film forming method is one of a sputtering method, a vacuum deposition method, and a CVD method. 
     
     
       3. A method according to  claim 1 , wherein said bridge structure and said protective layer are each in the form of one of an SiN thin film and an SiON thin film formed by a CVD method. 
     
     
       4. A method according to  claim 1 , wherein use is made, as said laser light, of laser light having a wavelength of 157 to 550 nm. 
     
     
       5. A method according to  claim 1 , wherein an irradiation energy of said laser light is set to 10 to 150 mJ/cm 2  . 
     
     
       6. A method according to  claim 1 , wherein irradiation of said laser light is performed at a substrate temperature of 350° C. or less. 
     
     
       7. A method according to  claim 1 , wherein irradiation of said laser light is performed in a vacuum or in a mixed reducing gas atmosphere. 
     
     
       8. A method according to  claim 4 , wherein use is made, as said laser light, of laser light having a wavelength of 222 to 360 nm. 
     
     
       9. A method according to  claim 5 , wherein an irradiation energy of said laser light is set to 30 to 60 mJ/cm 2 . 
     
     
       10. A method according to  claim 6 , wherein irradiation of said laser light is performed at a substrate temperature of room temperature.